CHICAGO -- The U.S. Justice Department has sent a letter to Chicago police superintendent Eddie Johnson warning that the department must prove it is complying with immigration law or risks losing millions of dollars in federal money.

Similar letters were sent to officials in New Orleans, Philadelphia, Milwaukee and the California corrections department. It’s the latest salvo in the Justice Department’s efforts to force so-called “sanctuary cities” into reporting illegal immigrants.

“Many of these jurisdictions are also crumbling under the weight of illegal immigration and violent crime,” a DOJ press release stated. “The number of murders in Chicago has skyrocketed, rising more than 50 percent from the 2015 levels.”

The Justice Department said Chicago and other “sanctuary cities” have until June 30 to provide documentation proving that they are cooperating with federal immigration authorities or may lose public safety and other federal grants.

The City’s 2017 anticipated grant awards from the Justice Department to the Chicago Police Department are about $10.7 million, city budget spokeswoman Molly Poppe said. Chicago's Justice Department grants include the following:

COPS Hiring Program - $3.1 million

Edward Byrne Memorial Justice Assistance Grant - $3.2 million

Asset Forfeiture - $3.7 million

Services to Victims of Domestic Violence - $238,000

Chicago Domestic Violence Help Line - $455,000

In addition, Poppe said the city has approximately $4 million to $5 million in carryover grant funds received from the Justice Department for prior fiscal years.

Chicago Mayor Rahm Emanuel issued the following statement: "We've seen the letter from DOJ. Neither the facts nor the law are on their side. Regardless, let me be clear: Chicago's values and Chicago's future are not for sale."